deoptigate -- node --allow-natives-syntax *.js

array-indexed property access benchmark.js

const { performance } = require('perf_hooks');

const h1 = (tag, props, children) => ({ tag, props, children })
const h2 = (tag, props, children) => ({ tag, props, children })

function serializeProps(props) {
  let out = '';
  for (let i in props) out += ` ${i}="${props[i]}"`;
  return out;
}

let start, end;
const ITER = 500000;

start = performance.now();
const vnodes1 = [];
for (let i=ITER; i--; ) {
  const vnode = h1('h'+i, {i}, ['index: ', i]);
  const html = `<${vnode.tag}${serializeProps(vnode.props)}>${vnode.children.join('')}</${vnode.tag}>`;
  vnode._rendered = html;
  vnodes1.push(vnode);
}
console.log(vnodes1.map(v => v._rendered).join('').length);
end = performance.now();
console.log('string: ', (end - start)|0);


start = performance.now();
const vnodes2 = [];
const RENDERED = 42;
for (let i=ITER; i--; ) {
  const vnode = h2('h'+i, {i}, ['index: ', i]);
  const html = `<${vnode.tag}${serializeProps(vnode.props)}>${vnode.children.join('')}</${vnode.tag}>`;
  vnode[RENDERED] = html;
  vnodes2.push(vnode);
}
console.log(vnodes2.map(v => v[RENDERED]).join('').length);
end = performance.now();
console.log('array: ', (end - start)|0);